This section provides background information related to the present disclosure and is not necessarily prior art.
Vehicles such as automobiles, for example, typically include at least one seat assembly that is movable in one or more directions (e.g., fore-aft, up-down, angular orientation, etc.) relative to a portion (e.g., a floor pan) of the vehicle in order to accommodate occupants of different size and height as well as to provide a comfortable seating position to suit the occupant's preference. Such seat assemblies often include at least one track assembly having an adjustment mechanism that allows the occupant or other user to move the seat assembly relative to the floor pan. Such adjustment mechanisms may be manually or electrically operated.
A manually operated adjustment mechanism commonly employs a rotatable knob or a lever that is manually pushed or pulled by the user to adjust the height and tilt position of the seat assembly, and a lever that is pushed or pulled by the user to adjust the seat fore and aft position of the seat assembly. An electrically operated adjustment mechanism commonly employs a bi-directional electric motor that rotates at an angular velocity as high as 3,000 revolutions per minute driving a worm member engaging a mating worm gear rigidly coupled to a driven nut that threadingly engages the threads of a fixed spindle shaft, forcing the nut and the housing subassembly in which the nut is rotated to translate fore-and-aft along the spindle shaft axis. Such worm gear drives may be sensitive to misalignment, and, further, may generate, propagate, and transmit undesirable vibrations and noise to the seat assembly and other portions of the vehicle. The entire driving mechanism consisting of the worm gear drive is mounted in a rigid housing, secured to an adjustment assembly that must minimize its axial displacement should a force of a predetermined magnitude be applied thereto. Accordingly, while conventional seat assemblies, including seat track and adjustment assemblies, allow a user to adjust the longitudinal position of the seat assembly relative to the vehicle floor pan, a continuous need for improvement in the relevant art remains.